Note: Descriptions are shown in the official language in which they were submitted.
CA 02878932 2015-01-09
WO 2014/011999
PCT/US2013/050291
MINING CABLE COUPLERS
BACKGROUND OF THE INVENTION
[0001] The present invention relates to cable connectors and, more
particularly, to cable
connectors of the type used for electrical cables in the mining industry,
which have insulators.
[0002] Heavy electrical cables are commonly used in the mining industry for
powering
equipment. Such cables are connected together by cable couplers or connectors.
These are
used in pairs, one coupler having a plurality of sockets which receive a
plurality of plugs in a
second coupler. The couplers may be mounted on skids so they can be pulled
about the job
site by means of the attached cables.
[0003] The plugs and sockets, both of which comprise elongated conductors, are
usually
surrounded by an insulator, typically having a cylindrical opening surrounding
each of the
conductors. These insulators are subject to failure due to accident or
environmental
conditions. This can lead to arcing across adjacent conductors or between one
or more
conductors and ground. An example of such a mining coupler is described, for
example, in
United States Patent No. 5,447,453 ("the '453 Patent").
[0004] Mining couplers are adapted from other electrical market products. The
mining
industry has unique requirements, such as: dragging the "plug and play"
connections
protected by metal sleds behind equipment, quick and reliable connect and
disconnect,
high environmental contamination and must operate near the rated current/power
levels.
These requirements differ from many electric utility applications such as
underground
residential distribution (URD). Electric utility market models of "plug and
play" designs
for applications such as underground residential distribution generally do not
see full
current loading, are in relatively clean environments and the mechanical duty
requirements are relatively low compared to mining. Many of the harsh service
environment requirements in mining are met by protecting the electrical
connector
through the use of a metallic case.
SUMMARY OF THE INVENTION
[0005] Embodiments of the present invention provide a mining cable coupler
including a
hollow body having a first end and a second end. An entrance fitting for an
electrical cable
1
CA 02878932 2016-08-22
30253-41
is at the first end of the body. An electrical connector mounting member
having a plurality of
electrical connector receiving apertures is adjacent the second end of the
body. A plurality of
electrical connectors are mounted in corresponding ones of the receiving
apertures. Each of
the electrical connectors includes an elongate electrical conductor and an
insulating material.
The elongate electrical conductor extends from a first end in the hollow body
that is
configured to electrically connect to an electrical cable received through the
entrance fitting to
an opposite second end that has an exposed face at the second end of the
hollow body. The
first end of the electrical conductor is closer to the first end of the hollow
body than the
second end of the electrical conductor. The insulating material surrounds the
electrical
conductor. At the second end of the electrical conductor, the insulating
material defines a
radiused region on the exposed end face of the electrical connector that
provides electrical
stress relief at the exposed end face. The second end of the electrical
conductor includes either
an electrically conductive pin portion protruding from the end face or a
mating electrically
conductive socket portion having an opening in the end face.
[0005a] The radiused region comprises either a concave or a convex region.
[0005b] The electrical connector mounting member comprises a substantially
flat mounting
plate.
[0005c] The electrical connector receiving apertures are defined in the
mounting plate.
[0005d] A plurality of annular recesses are defined between the mounting plate
and the
second end of the hollow body with one of the annular recesses surrounding a
respective one
of the electrical connector apertures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] Figure 1 is a side cross-sectional view illustrating a mining coupler
with male plugs
according to some embodiments of the present invention;
[0007] Figure 2 is a side cross-sectional view illustrating a mining coupler
with female
sockets according to some embodiments of the present invention;
2
CA 02878932 2016-08-22
=
30253-41
[0008] Figure 3 is a front plan view of the mining coupler of FIG. 1 with the
cover thereof
removed; and
[0009] Figure 4 is a front plan view of the mining coupler of FIG. 2 with the
cover thereof
removed.
DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0010] The present invention now will be described more fully hereinafter with
reference to
the accompanying drawings, in which illustrative embodiments of the invention
are shown. In
the drawings, the relative sizes of regions or features may be exaggerated for
clarity. This
invention may, however, be embodied in many different forms and should not be
construed as
limited to the embodiments set forth herein; rather, these embodiments are
provided so that
this disclosure will be thorough and complete, and will fully convey the scope
of the invention
to those skilled in the art.
2a
CA 02878932 2015-01-09
WO 2014/011999
PCT/US2013/050291
[0011] It will be understood that, although the terms first, second, etc. may
be used herein to
describe various elements, components, regions, layers and/or sections, these
elements,
components, regions, layers and/or sections should not be limited by these
terms. These
terms are only used to distinguish one element, component, region, layer or
section from
another region, layer or section. Thus, a first element, component, region,
layer or section
discussed below could be termed a second element, component, region, layer or
section
without departing from the teachings of the present invention.
[0012] Spatially relative terms, such as "beneath", "below", "lower", "above",
"upper" and
the like, may be used herein for ease of description to describe one element
or feature's
relationship to another element(s) or feature(s) as illustrated in the
figures. It will be
understood that the spatially relative terms are intended to encompass
different orientations of
the device in use or operation in addition to the orientation depicted in the
figures. For
example, if the device in the figures is turned over, elements described as
"below" or
"beneath" other elements or features would then be oriented "above" the other
elements or
features. Thus, the exemplary term "below" can encompass both an orientation
of above and
below. The device may be otherwise oriented (rotated 900 or at other
orientations) and the
spatially relative descriptors used herein interpreted accordingly.
[0013] As used herein, the singular forms "a", "an" and "the" are intended to
include the
plural forms as well, unless expressly stated otherwise. It will be further
understood that the
terms "includes," "comprises," "including" and/or "comprising," when used in
this
specification, specify the presence of stated features, integers, steps,
operations, elements,
and/or components, but do not preclude the presence or addition of one or more
other
features, integers, steps, operations, elements, components, and/or groups
thereof. It will be
understood that when an element is referred to as being "connected" or
"coupled" to another
element, it can be directly connected or coupled to the other element or
intervening elements
may be present. As used herein, the term "and/or" includes any and all
combinations of one
or more of the associated listed items.
[0014] Unless otherwise defined, all terms (including technical and scientific
terms) used
herein have the same meaning as commonly understood by one of ordinary skill
in the art to
which this invention belongs. It will be further understood that terms, such
as those defined
in commonly used dictionaries, should be interpreted as having a meaning that
is consistent
with their meaning in the context of this specification and the relevant art
and will not be
interpreted in an idealized or overly formal sense unless expressly so defined
herein.
3
CA 02878932 2015-01-09
WO 2014/011999
PCT/US2013/050291
[0015] Some embodiments of mining couplers will now be described with
reference to FIGs.
1 to 4. The coupler shown in FIGs. 1 and 3 is generally the same as that in
the embodiments
of FIGs. 2 and 4, however, the former includes male plugs adapted to be
received in the
female sockets of the latter. These embodiments are shown in FIGs. 1 and 2
with protective
covers 142, 156 in place. In normal use these covers would be removed and the
complementary couplers mutually engaged to connect together two different
mining cables.
Because of their similarities, the embodiments are chiefly described with
reference only to
the embodiment of FIGs. 1 and 3.
[0016] Referring now to FIGs. 1 and 3, the mining cable coupler 10 includes a
hollow body
12, which may be a metal such as aluminum. The body may be generally
cylindrical and has
a first end 14 and a second end 16 displaced longitudinally (along the axis of
the cable using
the coupler) from the first end 14.
[0017] An entrance fitting 24 is shown at the first end 14 of the body 12 that
receives an
electrical cable. The cable is received through a cylindrical interior opening
27. Seals and
other features of the entrance fitting 24 are shown, which are more fully
described, for
example, in the '453 Patent. Other types of entrance fittings may be used with
embodiments
of the present invention.
[0018] Also shown in the embodiments of FIGs. 1 and 3 is an insulated
connector member
mount, shown generally at 90, for mounting a plurality of insulated connector
members, such
as connector member 92 shown in FIG. 1 (see also, connector member 92' in FIG.
2),
adjacent the second end 16 of the body. In the illustrated embodiments, there
are three such
connector members 92, 94 and 96, shown in FIG. 3, as is conventional for
mining cable
couplers of this type. The connector members 92, 94, 96 are illustrated as
arranged at the
corners of an equilateral triangle. Unlike conventional mining coupler
insulators, which
include tubular insulators as seen in the '453 Patent, the connector members
92, 94, 96 (92',
94', 96') include a ball (convex end face) 92', 94', 96' and cup (concave end
face) 92, 94, 96
insulator configuration such as that more fully described in the context of
the electrical
connection disclosed in United States Patent No. 6,227,908 ("the '908
Patent").
[0019] The connector member mount 90 is shown as a generally round, plate-like
member.
The three connector members 92, 94, 96 are received in respective circular
apertures through
the connector member mount 90. Aperture 100 for connector member 92 can be
seen in FIG.
1 (See, also, connector member 92' in FIG. 2). The other apertures are the
same, and are
spaced-apart at the corners of an equilateral triangle to correspond with the
positions of the
connector members shown in FIG. 3. There is an annular recess 102 about each
aperture, 100
4
CA 02878932 2016-08-22
30253-41
on the side of mount 90 facing end 16 of the body. The recess is dimensioned
to be
complementary in shape and configuration to the shoulder 98 of each connector
member so
the shoulder can be closely received within the recess as shown for connector
member 92 in
FIG. 1.
[0020] An 0-ring may be compressingly received between each insulator and the
corresponding aperture in mount 90. These 0-rings may serve to seal about each
of the
insulators and may seal the inside of the body 12 from moisture, dirt and
other contaminants.
[0021] Connector member 92 has a metal conductor 214 extending therein within
insulating
material 216 with a pin 218 protruding therefrom at one end. At its other end,
beyond the
insulating material 216, the connector member 92 terminates in a socket 220
for receiving the
conductor of a high voltage cable received into the hollow body 12 through the
opening 27. At
the pin end of the connector member 92, the insulation 216 is radially
enlarged and may carry
a conductive screening layer 222 on its outer surface, the layer terminating
in a radial flange
224 that defines the shoulder 98. The insolation 216 may be radially enlarged
and radiused
(concave in FIG. 1) adjacent the pin 218 on the end face 250, so as to
distribute electrical
stress more evenly over the exposed annular end surface face 250 (i.e., the
"cup" of the ball
and cup insulator interface after forming an electrical connection) of the
insulation 216. Many
existing medium voltage insulating materials may be used for the insulation
216, 228.
Examples of suitable materials include silicone rubber and ethylene propylene
diene monomer
(M-class) rubber (EPDM). Mixtures could also be utilized for the dielectric.
High or medium
current/voltage pin and socket connectors could be employed based on the
connection
requirements.
[0022] Referring now to FIG. 2, the connector member 92' (i.e., female
connector member)
has a corresponding metal conductor 226 encased within insulating material
228. The
conductor 226 terminates at one end in a socket 230 that is configured to
receive the pin 218,
and at its other end is a socket 232 for receiving the conductor of another
cable. The connector
member 92' may also be provided with an outer conductive screening layer 234
terminating in
a flange 236 (defining the shoulder 98) at a radially-enlarged (convex in FIG.
2) insulating
5
CA 02878932 2016-08-22
30253-41
portion around the socket 230 (i.e., the "ball" of the ball and cup insulator
interface) at an end
face 252 of the connector member 92'.
[0023] The exposed mating annular surface faces 250, 252 of the connector
members 92, 92'
are curved (radiused) so as to assist in the exclusion of air pockets at the
interface when the
pin 218 is fully mated within the socket 230 and when the outer flanges 224
and 236 are in
abutment. The curved insulating interface may be offset from the annular
interface of the
5a
CA 02878932 2015-01-09
WO 2014/011999
PCT/US2013/050291
flanges 224,236 so as to avoid a direct path from outside the connector
members 92, 92 to
the inner high voltage conductor connection. Conductive layers 222 and 234,
together with
the flanges 224, 236 may provide screening of the interconnection.
[0024] A compact, low profile, screened and stress controlled in-line splice
can thus be
formed by the coupling of the electrical connector members 92, 92' when
respective cables
are connected to the sockets 220 and 232 thereof.
[0025] Referring again to FIG. 1, the coupler may also include a securing
member 118 which
may serve in part to releasably secure the connector members to mount 90. The
member 118
has an inner portion 120, shown in FIG. 1 and 3, which may be held tightly
against mount 90
by releasable fasteners, in this instance by three bolts 124. There are three
apertures 122
extending through inner portion 120 corresponding in position to each of the
connector
members 92, 94 and 96. The apertures 122 may be slightly larger than end faces
250, 252 of
the insulating material 216 apart from the shoulders 98 thereof. The apertures
are smaller
than the shoulders 98 and therefore the securing member 118 presses against
the shoulders of
the connector members to releasably secure them within the grooves 102 in the
insulator
mount 90 when the bolts 124 are tightened. Inner portion 120 then tightens
against both the
shoulders 98 of the connector members and the mount 90. The securing member
118 may be
made of metal.
[0026] FIG. 1 also shows a cap 142 fitted over the second end 16 of the body
12. A chain
152 may be used to connect the cap to the body 12, as seen in FIG. 3, so the
cover is not lost
when removed from the end 16 of the body as shown in FIG. 1 The cover is thus
removed in
order to connect coupler 10 with coupler 11 shown in FIG. 2.
[0027] Coupler 11, as mentioned above, is generally similar to coupler 10 and
therefore is
described only with respect to the differences therebetween. In the case of
coupler 11, cap
156 for this coupler is instead provided with the spaced-apart lugs 159 which
to attach to the
body of the coupler 10. The cap 156 is removed in order to connect coupler 10
to coupler 11.
As discussed above, coupler 11 has three female sockets 230 configured to
receive the male
plugs 218 of coupler 10. There are three such sockets that are arranged and
spaced-apart in
the same manner as the male plugs so as to allow all three connections to be
concurrently
formed by a simple longitudinal insertion.
[0028] A securing member 166 of the coupler 11 is flat and plate-like. With no
outer tubes
surrounding the insulator.
[0029] After the covers are removed, the couplers can be fitted together, end
170 of coupler
11 being larger in diameter than end 16 of coupler 10 so the latter receives
the former therein
6
CA 02878932 2015-01-09
WO 2014/011999
PCT/US2013/050291
up to shoulder 144 of coupler 10. The couplers 10, 11 may then be tightened
together by a
bolt as illustrated to hold the couplers together.
[0030] As described above, embodiments of the present invention adapt a ball
and cup
configuration connector to provide improved mining couplers. These connectors
include a
male and female dielectric interface with the abutting faces thereof in a ball
and cup
relationship for the interface between the dielectrics with the power passed
through a center
pin (plug) and socket connector. It will be understood that, while the plug is
shown as having
the concave end face 250, in other embodiments the plug has a convex end face
and the
mating socket has a concave end face 252.
[0031] Many existing mining couplers, equipment plug ports and supply plug
ports utilize
male and female tubular or conical bushings similar to the electric utility
load break and dead
break 200A, 250A & 600A 15kV-35kV designs. While this design may be acceptable
for
the electrical utility application of connecting one phase at a time, the
mechanical,
environmental and service requirements are moderate. Mining applications, such
as
described in the '453 Patent, generally require all 3 phases to be connected
at once with a long
longitudinal interface between the insulating dielectrics in harsh
environments. The tough
service conditions for these conventional couplers all contribute to damage
and electrical
breakdown with this configuration.
[0032] The ball and cup configuration of some embodiments of the present
invention may
provide a quicker and easier make and break interface as compared to the
relatively large
surface area of three tubular or conical bushings and rubbing of the
dielectrics during
insertion of the connectors. Bending moments and torques would be limited as
the make and
break of the electrical connection would require much less "X" axis or
longitudinal
movement because the insulating dielectric interface is now more along the "Y"
axis or
normal to the make and break axis as seen in FIGs. 1 and 1
[0033] In some embodiments, connector members as described herein could be
used to adapt
existing couplers one phase at a time if one coupler insulator was damaged. A
female
dielectric cup would be put on the appropriate coupler connector and the male
on the other.
The interface between the existing couplers around the damaged insulator could
be
accomplished by mechanical force or pressure of mating the outer coupler
housings or high
dielectric grease or high dielectric gel. The same method could be applied
phase by phase or
with a 3 phase retrofit design if the entire already in use coupler was to be
converted.
[0034] In some embodiments of the present invention, the electrical connection
may be
protected from excessive mechanical dielectric and connector forces by the
coupler housing
7
CA 02878932 2015-01-09
WO 2014/011999
PCT/US2013/050291
making the ball and cup configuration described herein an excellent medium
voltage power
connection for this mining coupler application.
[0035] The foregoing is illustrative of the present invention and is not to be
construed as
limiting thereof Although a few exemplary embodiments of this invention have
been
described, those skilled in the art will readily appreciate that many
modifications are possible
in the exemplary embodiments without materially departing from the novel
teachings and
advantages of this invention. Accordingly, all such modifications are intended
to be included
within the scope of this invention as defined in the claims. In the claims,
means-plus-
function clauses are intended to cover the structures described herein as
performing the
recited function and not only structural equivalents but also equivalent
structures. Therefore,
it is to be understood that the foregoing is illustrative of the present
invention and is not to be
construed as limited to the specific embodiments disclosed, and that
modifications to the
disclosed embodiments, as well as other embodiments, are intended to be
included within the
scope of the appended claims. The invention is defined by the following
claims, with
equivalents of the claims to be included therein.
8
